Abstract:
:We develop parametric maximum likelihood methods to adjust for treatment changes during follow-up in order to assess the causal effect of treatment in clinical trials with time-to-event outcomes. The accelerated failure time model of Robins and Tsiatis relates each observed event time to the underlying event time that would have been observed if the control treatment had been given throughout the trial. We introduce a bivariate parametric frailty model for time to treatment change and time to trial endpoint. Estimating equations which respect the randomization are constructed and compared to maximum likelihood methods in a simulation study. The Concorde trial of immediate versus deferred zidovudine in HIV infection is used as a motivating example and illustration of the methods.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Walker AS,White IR,Babiker AGdoi
10.1002/sim.1618subject
Has Abstractpub_date
2004-02-28 00:00:00pages
571-90issue
4eissn
0277-6715issn
1097-0258journal_volume
23pub_type
杂志文章abstract::The back-calculation method has been used to estimate the number of HIV infections from AIDS incidence data in a particular population. We present an extension of back calculation that provides estimates of the numbers of HIV infectives in different stages of infection. We model the staging process with a time-depende...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780110612
更新日期:1992-04-01 00:00:00
abstract::The publication of Fisher's correspondence on statistics has shed new light on his views on randomization. Quotations from this correspondence and from other works of Fisher are used to illustrate the role of randomization in clinical trials. It is concluded that Fisher's views not only are coherent but, despite havin...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130305
更新日期:1994-02-15 00:00:00
abstract::We extend the method proposed in a recent work by the Authors for trial-level general surrogate evaluation to allow combinations of biomarkers and provide a procedure for finding the "best" combination of biomarkers based on the absolute prediction error summary of surrogate quality. We use a nonparametric Bayesian mo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7996
更新日期:2019-03-30 00:00:00
abstract::Reference ranges which take time (such as age) into account are often required in medicine, but simple, systematic and efficient statistical methods for constructing them are lacking. A method is described which is based on low order polynomial curves (linear, quadratic or occasionally cubic), together with guidelines...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1002/sim.4780100502
更新日期:1991-05-01 00:00:00
abstract::Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximu...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3414
更新日期:2009-01-15 00:00:00
abstract::The original article to which this Correction refers was published in Statistics in Medicine 2000 19(14): 1901-1914. ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20001115)19:21<3017::aid-sim785>
更新日期:2000-11-15 00:00:00
abstract::An observed confidence distribution is proposed as a measure of strength of evidence for practically equivalent efficacies of two treatments. The concept is independent of prior opinions about relevant sizes of a difference in efficacy. It also avoids retrospective power calculations for trials with missed recruitment...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780071207
更新日期:1988-12-01 00:00:00
abstract::In this commentary, we revisit Sir Austin Bradford Hill's seminal Alfred Watson Memorial Lecture in 1962 through the eyes of two practicing biostatisticians of the current era. We summarize some eternal takeaway messages from Hill's lecture regarding observations and experiments translated through the modern lexicon o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8830
更新日期:2021-01-15 00:00:00
abstract::Juvenile dermatomyositis (JDM) is a rare autoimmune disease that may lead to serious complications, even to death. We develop a 2-state Markov regression model in a Bayesian framework to characterise disease progression in JDM over time and gain a better understanding of the factors influencing disease risk. The trans...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7613
更新日期:2018-05-10 00:00:00
abstract::Although the literature on contraceptive failure is vast and is expanding rapidly, our understanding of the relative efficacy of methods is quite limited because of defects in the research design and in the analytical tools used by investigators. Errors in the literature range from simple arithmetical mistakes to outr...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.4780100206
更新日期:1991-02-01 00:00:00
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journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3497
更新日期:2009-03-15 00:00:00
abstract::In comparing two treatments under a typical sequential clinical trial setting, a 50-50 randomization design generates reliable data for making efficient inferences about the treatment difference for the benefit of patients in the general population. However, if the treatment difference is large and the endpoint of the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19961130)15:22<2413::aid-s
更新日期:1996-11-15 00:00:00
abstract::One may encounter the application of the two independent samples t-test to ordinal scaled data (for example, data that assume only the values 0, 1, 2, 3) from small samples. This situation clearly violates the underlying normality assumption for the t-test and one cannot appeal to large sample theory for validity. In ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780060110
更新日期:1987-01-01 00:00:00
abstract::A survey is conducted at w of K selection units or lists, e.g. health care institutions or weeks in a year, to estimate N, the total number of individuals with particular characteristics. Our estimator utilizes two items determined for each survey participant: the number, u, among the w lists in S and the number, j, a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3614
更新日期:2009-07-30 00:00:00
abstract::Health surveillance involves collecting public health data on chronic and infectious diseases to detect changes in disease incidence rates in order to improve public health. Timely detection of disease clusters is essential in prospective public health surveillance. Most existing health surveillance research is based ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3877
更新日期:2011-02-28 00:00:00
abstract::Linear mixed effects (LME) models are increasingly used for analyses of biological and biomedical data. When the multivariate normal assumption is not adequate for an LME model, then a robust estimation approach is preferable to the maximum likelihood one. M-estimators were considered before for robust estimation of t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4169
更新日期:2011-06-30 00:00:00
abstract::Two correction methods are considered for multiple logistic regression models with some covariates measured with error. Both methods are based on approximating the complicated regression model between the response and the observed covariates with simpler models. The first model is the logistic approximation proposed b...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780131105
更新日期:1994-06-15 00:00:00
abstract::In this study, 401 cases of childhood cancer in four California counties in 1980-1988 were analysed with the innovative methodology of density equalizing map projections. The data were originally collected and analysed by the California State Department of Health Services (DHS). In addition to the new analytic techniq...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.686
更新日期:2001-05-15 00:00:00
abstract::In analysis of longitudinal data, the variance matrix of the parameter estimates is usually estimated by the 'sandwich' method, in which the variance for each subject is estimated by its residual products. We propose smooth bootstrap methods by perturbing the estimating functions to obtain 'bootstrapped' realizations ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3027
更新日期:2008-03-30 00:00:00
abstract::Log-linear models for capture-recapture type data are widely used for estimating sizes of populations. Log-linear methods model conditional interactions between the sources. Often, however, the marginal associations are more appropriate and easier for the practitioner to conceptualize. Analyses here of previously publ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19980115)17:1<69::aid-sim7
更新日期:1998-01-15 00:00:00
abstract::We consider counting process methods for analysing time-to-event data with multiple or recurrent outcomes, using the models developed by Anderson and Gill, Wei, Lin and Weissfeld and Prentice, Williams and Peterson. We compare the methods, and show how to implement them using popular statistical software programs. By ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970930)16:18<2029::aid-s
更新日期:1997-09-30 00:00:00
abstract::Mediation analysis is a standard approach to understanding how and why an intervention works in social and medical sciences. However, the presence of missing data, especially missing not at random data, poses a great challenge for the applicability of this approach in practice. Current methods for handling such missin...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7413
更新日期:2017-11-10 00:00:00
abstract::Clinical studies that involve the recording of two or more distinct and well-defined events on each subject give rise to multiple event data. Treatment comparisons are usually reported in univariate analyses of time to first event or number of events observed. However, this approach may not uncover the 'full story' of...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,多中心研究,随机对照试验
doi:10.1002/(sici)1097-0258(19970430)16:8<941::aid-sim
更新日期:1997-04-30 00:00:00
abstract::In this paper the following problem of clinical research is explored. Several potential new treatments are available for use against a certain disease. These are evaluated in a series of pilot studies which will constitute phase II clinical trials. The most promising will then be compared with a standard treatment in ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780050510
更新日期:1986-09-01 00:00:00
abstract::Many split-mouth trials are characterized by the pairing of site-specific outcome and baseline data within each segment of a subject's mouth. However when the response variable of interest is binary, methods of statistical analysis for this design are not well developed. In this paper we present several analytic appro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2782
更新日期:2007-08-15 00:00:00
abstract::In medical research, a two-phase study is often used for the estimation of the area under the receiver operating characteristic curve (AUC) of a diagnostic test. However, such a design introduces verification bias. One of the methods to correct verification bias is inverse probability weighting (IPW). Since the probab...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8700
更新日期:2020-11-30 00:00:00
abstract::Differences between arm-based (AB) and contrast-based (CB) models for network meta-analysis (NMA) are controversial. We compare the CB model of Lu and Ades (2006), the AB model of Hong et al(2016), and two intermediate models, using hypothetical data and a selected real data set. Differences between models arise prima...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8360
更新日期:2019-11-30 00:00:00
abstract::Various R(2) statistics have been proposed for logistic regression to quantify the extent to which the binary response can be predicted by a given logistic regression model and covariates. We study the asymptotic properties of three popular variance-based R(2) statistics. We find that two variance-based R(2) statistic...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2300
更新日期:2006-04-30 00:00:00
abstract::This paper describes the Stoke Index which has been designed to give a global measure of disease activity in rheumatoid arthritis. The index is based on two objective laboratory measurements, one subjective and two semi-objective clinical measurements, chosen from 13 measurements using clinical judgement. Variable sel...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780121206
更新日期:1993-06-30 00:00:00
abstract::We studied the problem of testing a hypothesized distribution in survival regression models when the data is right censored and survival times are influenced by covariates. A modified chi-squared type test, known as Nikulin-Rao-Robson statistic, is applied for the comparison of accelerated failure time models. This st...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7244
更新日期:2017-05-30 00:00:00